What is leukemia?

Cancer starts when cells change (mutate) and grow out of control. Leukemia is cancer that starts in cells in the bone marrow and blood. The bone marrow is the thick, spongy liquid inside of bones. It's where blood cells are made.

The blood is made up of 3 main types of cells:

• White blood cells fight infection and disease.

• Red blood cells carry oxygen all through the body to give a person energy.

• Platelets help the blood clot to stop bleeding.

Leukemia usually affects the white blood cells. Healthy white blood cells form in the bone marrow. But with leukemia, large numbers of abnormal, immature white blood cells called are made. These are called leukemia cells or blasts. Blasts live longer than normal white blood cells and crowd out the healthy cells. They do not mature and function like healthy while blood cells. As time goes on, there are more blasts than healthy cells. Then the blood can’t do its job. This leads to problems like infections and bleeding. It can also cause anemia. This occurs when there are too few red blood cells.

Leukemic blasts are abnormal white blood cells. Their shape and size are different than those of normal white blood cells.

Who gets leukemia?

Leukemia is the most common type of childhood cancer in the U.S. Children at any age can get leukemia. But younger children are affected most often.

Leukemia is not contagious. This means it can’t be passed from person to person.

What causes leukemia?

Leukemia starts when white blood cells change and don't grow the way they should. What causes this to happen is not fully known.

Changes in certain genes, called mutations, may affect the way your child’s cells grow. But this gene mutation is random and couldn’t have been prevented. In rare cases, other factors might play a role. These can include certain inherited conditions. Or exposure to certain chemicals or radiation. But most often, the cause of leukemia in children is unknown.

Types of leukemia

There are many different types and subtypes of leukemia. They are classified by how quickly the leukemia progresses. Acute leukemias progress quickly. Chronic types more progress slowly. It is much more common for children to have acute leukemias than chronic leukemias. Leukemia is also classified by the blood cell type, such as lymphoid or myeloid cells. The main types of leukemia that affect children include:

• Acute lymphoblastic leukemia (ALL) is the most common leukemia in children. ALL occurs when the body makes abnormal, immature white blood cells called lymphoblasts. These cells don't grow into healthy white blood cells the way they should to fight infection. ALL is a fast-growing cancer.

• Acute myelogenous leukemia (AML) is the second most common leukemia in children. AML occurs when the body makes abnormal blood cells called myeloid blasts. These cells don't grow into healthy white blood cells, red blood cells, or platelets the way they should. AML tends to grow quickly.

• Chronic myelogenous leukemia (CML) is rare in children. CML occurs because the body makes abnormal myeloid cells (much like AML). With CML, the white blood cells are more mature, but there are too many of them. CML develops more slowly than AML.

• Juvenile myelomonocytic leukemia (JMML) is another rare type of leukemia in children. It's most often seen in children younger than age 2. JMML starts in myeloid cells and makes too many myelocytes and monocytes. But it often doesn't grow as fast as AML or as slow as CML.

Your child's healthcare provider will talk with you about the type of leukemia your child has and what it means. Ask your child's provider to explain the details of the cancer to you in a way you can understand. Ask any questions and talk about your concerns.

What are the symptoms of leukemia?

Some common symptoms of leukemia include:

• Fever

• Infections that don't go away

• Pale skin

• Easy bruising or bleeding

• Bone or joint pain

• Swollen lymph nodes

• Swelling and pain in the abdomen (belly)

• Flat red dots on the skin that look like a rash

• Feeling very tired (fatigue)

• Shortness of breath with normal physical activities

• Weakness

• Weight loss

Many of these may be caused by other health problems. It's important that your child see a healthcare provider if they have these symptoms. Only a healthcare provider can tell if your child has cancer.

How is leukemia diagnosed?

The healthcare provider will ask you about your child’s symptoms, health history, and family history. A physical exam will be done. Your child may also have blood tests done. These help the provider see how well your child’s bone marrow is working and get an idea of their overall health.

If your provider thinks your child has leukemia, you'll likely be referred to a pediatric oncologist. This doctor has special training in treating cancer in children. Other tests may be needed to learn more about the exact type of leukemia your child has. These can include:

• More blood tests. These are done to gather more detailed information and to look at blood cells under a microscope.

• Bone marrow aspiration and biopsy. This is done to take out a small piece (sample) of bone marrow for testing.

• Lumbar puncture (spinal tap). This test takes a sample of the fluid that surrounds the spinal cord and brain. The fluid is then checked for leukemia cells.

How is leukemia treated?

Chemotherapy (chemo) is the main treatment used for most types of leukemia. It uses strong medicines to destroy cancer cells. The kind of chemo your child gets depends on the type of leukemia your child has. Many times, a combination of chemo medicines is used. The medicines may be given by mouth, injection, or right into the blood through a tube (IV) that’s put into a vein. Some children might benefit from high-dose chemo followed by a stem cell transplant.

A type of immunotherapy called chimeric antigen receptor (CAR) T-cell therapy may be a treatment choice for some children with ALL. Your child’s provider can tell you more about treatment choices that are right for your child.

Children with ALL, AML, and CML may get a type of medicine called targeted therapy with or instead of chemo. These medicines attack certain changes inside the ALL, AML, and CML cells.

Radiation may be part of the treatment plan in certain cases. In rare cases, surgery is used to treat leukemia.

Supportive treatments

Supportive treatments help protect your child from infection, prevent discomfort, and bring their blood counts into a healthy range. During your child’s treatment, antibiotics might be given to help prevent and fight infection. Other medicines may also be needed to help ease side effects caused by chemo. These can include nausea, diarrhea, and mouth sores. Your child may also need blood transfusions to restore the blood cells. These supportive treatments don't directly treat the leukemia. But they help with problems caused by the leukemia or treatment.

What are the long-term concerns?

Leukemia in children can often be cured with treatment. But chemo can cause problems, such as damage to certain organs, like the heart, bones, or lungs, and other long-term side effects. There may be fertility issues or risks for another type of cancer in the future. Your child’s health will need to be watched closely for life. This may include clinic visits, blood tests, and imaging scans. Most children cured from leukemia can expect to live typical lives. But they may need some extra medical care. And they may have some long-term medical issues.

Coping

Hearing your child has cancer is scary and confusing. Remember that you're not alone. Your child’s healthcare team will work with you, your family, and your child during your child’s illness and care.

You may want to look for information and support for you and your family, too. Doing so can help you cope with the changes cancer brings. Learning about your child's cancer and talking with others who also have a child with cancer may help you and your family cope and know what to expect. Some helpful resources include:

• Children's Oncology Group at www.childrensoncologygroup.org/index.php/patients-and-families

• Children’s Leukemia Research Association at www.childrensleukemia.org

• The Leukemia & Lymphoma Society at https://www.lls.org/